In the telecommunication industry, light can be used advantageously as an information carrier. A special problem in this field of technology resides in the devices for dividing and combining light signals. A number of solutions to this problem are presented in the article "Verzweigungseinrichtungen fur Lichtwellenleiter" by F. Auracher and others in the magazine "Siemens Forschungs und Entwicklungsberichte" Volume 5 (1976) no. 1.
Basically, two types of branching devices for light signals are known, which work by the following methods respectively: